In the dog lover community, it is known that smaller dogs tend to live much longer than big dogs, but no one knows the reasons behind this fact.

Here’s what we know thanks to the study lead by Cornelia Kraus, “The size-lifespan trade-off decomposed: Why large dogs die young”, published in The American Naturist.

 Larger Dogs Age Faster

Scientists over the years have found that the lives of dogs seem to speed up the bigger they are. Every 2 kgs (4.4 pounds) takes a month out of their lives.

However, some data shows that in some cases, dogs that are the same size and weight have different age limits. For example, a dog that weighs 40 to 50 pounds: one breed with these characteristics may live up to 13 years, while another breed with the same characteristics may only live up to 9 years. The theory on why this happens is due to the fact that many of these dogs were bred by humans for multiple reasons, without regards for the health of these breeds. The average lifespan for big dog breeds continues to be 8-9 years average, and this theory is not considered one of the top reasons for their short lifespans.

Big dogs also tend to grow faster in the sense of becoming adults rather quickly. The change from puppy to adult seems to happen sooner in big dogs than in the smaller breeds, which leads us to our next point.

Likeliness to Acquire an Illness

Larger breeds seem to get sicker more than small breeds, contributing to their lifespan differences. The most likely hypothesis to why this happens is the growth speed. Since they grow older faster, they also acquire the diseases that come with old age, and their systems deteriorate earlier. Another hypothesis linked to this is the likelihood of their cells creating cancerous masses due to their speed. This could also be used to explain why they could have other illnesses, however, this option has not been fully pursued and therefore there is not much data regarding it.

Risks Taken on a Daily Basis

Last but not least, we have the less likely hypothesis, the risks. Although it is true that larger breeds such as the Great Dane tend to lead riskier lives than smaller breeds such as the Pomeranian, it is an unlikely scenario to be the cause of their shorter lifespan. It is believed this factor contributes to the small lives of big dogs. Due to its unlikeliness, however, this hypothesis has not been investigated thoroughly, and we can only conclude this to not be the main reason.

Whichever the reason our big buddies tend to live less, they provide a company worth experiencing, and we give them lives to remember. A dog will always be our best friend, and we must make sure to also be theirs.

More studies in the future will hopefully shed light on the reasons behind the connection between a dog’s lifespan and their size. Let’s try to make all of our dogs have happy lives meanwhile!

Want to learn more about dog breeds of all sizes? Visit our guide to dog breeds of the world!


This guest post was provided by Dogsora